You're setting up a shared printer or a network drive on a Windows machine, and just as you hit OK, the whole thing blows up with 0X00000A51 and the message "The configuration name is in use by some other configuration". Usually happens when you're creating a new remote boot configuration, or when you're trying to add a second config with the same name to the same server. I saw this last month on a client's old Windows Server 2008 box running Remote Installation Services (RIS). They had two identical configs named "Standard" and the second one refused to write.
What's actually going on
This error is NERR_RplConfigNameUnavailable from the Remote Program Load (RPL) subsystem. Windows keeps a list of configuration names in a specific spot, and that list doesn't allow duplicates. If you've got a leftover config from a previous attempt, or two admins created the same name on different days, Windows throws this error. It's not a permissions thing, it's not a driver issue — it's purely a name collision.
The fix (numbered steps)
- Open the RPL manager. Go to Start > Administrative Tools > Remote Installation Services. If you're not on a server, you'll need to use the command line tool
rplmgr.exefrom an elevated command prompt. - List all configurations. In the RPL manager, right-click on Configurations and choose Properties. You'll see every config name that's registered. Look for the one you're trying to add — it's probably sitting there already.
- Rename or delete the existing config. If the duplicate is old and unused, right-click it and select Delete. If you need it for another machine, right-click and choose Rename, then give it a unique name like
Standard2. - Also check the registry. If the RPL manager shows nothing, the duplicate might be hiding in the registry. Open
regeditand go to:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Rpl\ConfigurationsLook for a key with the same name as your config. If it's there, right-click and export it as a backup, then delete it. Restart the RPL service with net stop rpl and net start rpl from an admin command prompt.
- Try adding your config again. Go back to the RPL manager, right-click Configurations, select New, and enter your name. Should go through without the error.
If it still fails
Sometimes the duplicate isn't in the RPL store — it's in the DHCP database. On a server running DHCP, open the DHCP console, find the scope, and look at Advanced > Boot Options. You might see an old boot image name that matches your config. Delete that entry.
Another sneaky one: a second network adapter on the same machine with a different config name but the same description. Windows treats the description as part of the config identity. So if your NIC's description is "Realtek PCIe GbE Family Controller" and you've got two NICs with that same description, you'll hit this even with different config names. Fix it by opening Device Manager, finding the duplicate NIC, and changing its description via Properties > Advanced > Network Address to something unique.
If you're still stuck, reboot the server. Sounds dumb, but I've seen the RPL service hold on to a stale handle after a failed write. A clean restart clears that and often gets you past 0X00000A51 without any registry surgery.
One last thing: if you're on Windows 10 or 11 and you're getting this while setting up a network printer, it's the same root cause — the printer's config name is taken. Go to Settings > Printers & Scanners, click the printer, and choose Manage > Printer Properties. Look for the "Configuration" section and rename it. That'll clear the collision.